One or more embodiments of the present invention pertain to method and apparatus to modify process recipes in apparatus utilized, for example, and without limitation, to fabricate integrated circuit (xe2x80x9cICxe2x80x9d) devices.
FIG. 1 is a pictorial representation of prior art wafer processing system 100 that is utilized to fabricate integrated circuit (xe2x80x9cICxe2x80x9d) devices. As shown in FIG. 1, wafer processing system 100 comprises one or more process cells 103-105, wafer transfer system 121, and factory interface 122. Each of process cells 103-105 is configured to perform a process on a wafer such as, for example, and without limitation, a chemical vapor deposition (CVD) process, a physical vapor deposition (PVD) process, an electro-chemical plating (ECP) process, and so forth. Factory interface 122 includes cassette loadlock 123. Cassette loadlock 123 stores one or more wafer cassettes, and individual wafers are moved from cassette loadlock 123 to process cells 103-105 by wafer transfer system 121. Further, the functions performed by wafer processing system 100, and the order in which these functions are performed, are controlled by tool controller 200. Tool controller. 200 is connected to each of the above-described system components in a manner that is well known to those of ordinary skill in the art to provide data and instructions thereto, and to receive data therefrom. In particular, with respect to process cells 103-105, at least a portion of the data and instructions provided thereto includes information that is referred to herein as xe2x80x9cprocess recipe informationxe2x80x9d or process recipes or recipes. As is well known to those of ordinary skill in the art, a recipe specifies, among other things, timing, duration, and sequences of events that take place in a processing cell. As such, a recipe may be utilized, for example, to activate gas valves to enable gases to enter a process cell, to set ratings for heaters to enable process temperatures to be set, to set ratings for pumps to enable process pressures to be set, and so forth.
As is well known, wafer processing systems like that shown in FIG. 1 are designed to provide substantially similar processing results (i.e., within predetermined manufacturing tolerances) for as long as possible. Further, as dimensions used to fabricate IC devices become smaller, manufacturing tolerances are becoming smaller and deviations from such tolerances are becoming more costly. As such, there is a substantial benefit in discovering processing results that exceed the predetermined manufacturing tolerances. The benefit accrues when, for example, a process cell that is producing poor processing results is identified and removed from service. This is advantageous because a source of defective IC devices is removed from service in the factory, and waste is reduced.
However, it has been determined that additional benefits can be had by studying processing results, and identifying a tendency of a process cell to produce processing results that (while being within manufacturing tolerance limits) are approaching tolerance limits. Further, it has been determined that such additional benefits can be obtained in such instances by taking two types of actions. The first type of action is to modify processing recipes of downstream wafer processing systems to compensate for processing results produced by an identified process cell. The second type of action is to modify processing recipes of the identified process cell to cause its processing results to be closer to a center of the tolerance limit range. These actions provide still further benefits in that they may prolong the time before processing cells have to be taken out of service for maintenance.
In light of the above, there is a need for method and apparatus to enable such new or modified recipes to be transmitted to and used by, wafer processing systems.
One or more embodiments of the present invention advantageously satisfy the above-identified need. In particular, one embodiment of the present invention is a method for modifying process recipe information utilized by a wafer processing system having a controller with permanent rewritable storage, memory, a first and a second communication interface, and a user interface; and one or more process cells to process a wafer; which method comprises steps of: (a) storing baseline process recipe information in permanent rewritable storage; (b) retrieving baseline process recipe information from permanent rewritable storage for a wafer in a group of wafers to be processed and storing it in memory; (c) receiving process recipe modification information utilizing the second communication interface and storing the process recipe modification information in memory; (d) overwriting at least portions of the baseline recipe information in memory with the process recipe modification information to form new recipe information; and (e) processing the wafer utilizing the new recipe information.